The Distribution of N, P and K in Abandoned Rubber Estate

Aims: This study examined the distribution of N, P and K in 30 years abandoned rubber estates in terms of soil fertility.

Study Design: Ten blocks were established by using grid systems.

Place and Duration of Study: The study was conducted in UPM Bintulu Campus, Sarawak at an abandoned rubber estate planted to RRIM600 and GT1 clones in 1986. The soil samples were collected between January to December 2016.

Methodology: Ten blocks (20 m x 50 m) were established in 7 ha actively tapped area. Land elevation levels for each block was recorded using GPS and classified into LE (38-43), ME (44-49) and UE (50-55) m above sea level. Surface soil samples were collected and analysed for total organic carbon, pH, total N, available P, K, Ca, Mg, Fe and Mn.

Results: There was no significant effect of elevation level on pH, N, P, K, Mg, Fe and Mn. However, Principal Component Analysis revealed insufficient organic carbon and N with effect on latex production.

Conclusion: Practising proper estate management such as proper fertilizer application, legume establishment and terracing were recommended to improve rubber productivity.